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Circulation of cerebrospinal fluid CSF
* * Purulent Meningitis
in Children Jiang Li Department of Neurology Children’s Hospital
Chongqing University of Medical Sciences
Acute infection of central nervous system CNS . 90% of cases occur in the age of 1mo-5yr.
The inflammation of
meninges caused by mon features in clinical practices include: fever, increased intracranial pressure, meningeal irritation. ?
the most potentially serious infections, associated with high mortality
and morbidity.
Purulent Meningitis Etiology
Pathogens: Main pathogens: Neissria meningitidis, streptoccus pneumoniae,
Haemophilus influenzae.
2/3 of purulent meningitis are caused by these pathogens
Pathogens in special populations
3mo infants , malnutrition, immunodeficiency :
gramnegative enteric bacilli, group B streptococci, staphlococcus aureus
Major risk factors for meningitis
Immature immunologic function
and attenuated
immunologic response to pathogens
? Low level of immunoglobulin, defects of
complement
and properdin system
? Immature or impaired blood-brain-barrier
? Immature BBB function: maturation at about 1yr
? Impaired BBB: Congenial or acquired defects
across mucocutaneous barrier
Access of bacteria invasion
Typical access---hematogenous dissemination
? Bacteria colonizing the mucous membranes of
the nasopharynx ?invasion into local tissue ?
bacteremia ? hematogenous seeding to the
subarachnoid space
? Mode of transmission: Person to person contact
through respiratory tract secretions or droplets
Bacteria spread to the meninges directly:
through anatomic defects in the skull or
head trauma
Invasion from parameningeal organs:
such as paranasal sinuses or middle ear Access of bacteria invasion 2.
Structure of meninges
Characterized by leptomeningeal and
正在加载中，请稍后...Researchers create transistors out of nanowire forests, for ‘ultimate scaling’ beyond 10nmBy
on May 1, 2013 at 2:00 pmShare This articleAs transistor size decreases, the limits of planar technologies have been partially alleviated by stepping into the third dimension. Gate leakage and capacitance issues can be minimized through technologies like FinFET, in which the metal gate wraps around a fin of silicon, or possibly even indium gallium arsenide (IGA). Nanowire-based transistors also have many advantages for 3D however, their small size typically cannot handle enough current for efficient function. One obvious solution to construct these “gate-all-around” transistors is to instead use a forest of nanowires all under control of the same gate. That approach is now the focus of some exciting new work being done in France at the Laboratory for Analysis and Architecture of Systems.Researchers in Japan had previously constructed an IGA-based nanowire transistor composed of 10 wires grown on a silicon base. That device showed good electrical behavior, but was much too large to be the new technology of choice. According to IEEE Spectrum, the new French design is . Each wire has a 14nm-thick chromium layer surrounding its midsection, which acts as the gate. The all-around design is a must if gate lengths are to get below lengths of 10nm.Fortunately there isn’t any new, complicated lithography involved in the manufacturing process. The researchers plan to eventually
because of their better electron mobility. While the architecture of the nanowire forest design is certainly more complex than FinFET’s, there is a clear path to simplification by reducing the total number of nanowires needed. Having control over individual elements — that are 30nm in diameter at the chip level — has obvious advantages over other
like gas-phase synthesis.Research on nanowires is actively being pursued at many institutions around the world. The French scientists believe that their proposed architecture offers several advantages over other nanowire designs. Chief among them are the reduction of device-to-device variability, and nanometer gate length patterning without the need for high-resolution lithography. For large-scale manufacture of devices, like low-power transistors and memory devices, these will be important benefits.It is worth noting that these new designs, where a gate completely envelops a wire to optimize surface of contact and reduce leakage, are highly reminiscent of neural structures. In the connections between neurons, synapses dynamically adopt a specialized geometry that suits the transmission needs of the connection. As with nanowire transistors, this geometry converges upon a form where reliable transmission occurs with the least energy expenditure. Being self-assembled, biological forms have the unique capacity to readily adapt flexible curved forms — synaptatic structure rises and falls on the convexity of an interface. Who has been doing what, and to whom, can be read from an electron micrograph of a slice of brain like a skilled geologist might read a sample of rock strata through time.The hard edges of semiconductor structures are a necessary side effect of our current technology. If the design file calls for 225 nanowire pillars with 30nm widths, than that is what will be made. Eventually the spec callouts may be defined by currents and temperatures, rather than by diameters, with the nanowires then apportioning themselves accordingly — but that is a technology for another day.Now read: Research Paper:
– “Vertical nanowire array-based field effect transistors for ultimate scaling”
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Ziff Davis, LLC.PCMag Digital Group All Rights Reserved. ExtremeTech is a registered trademark of Ziff Davis, LLC. Reproduction in whole or in part in any form or medium without express written permission of Ziff Davis, LLC. is prohibited.Double-checked preoperative localization of brain lesions.
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A):552-4. Epub
2003 Sep 16.Double-checked preoperative localization of brain lesions.1, , , .1Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil. .brAbstractWe describe two simple methods that can be used together or alone to localize brain convexity lesions. These methods are based on computerized tomography or magnetic resonance imaging to calculate the position of a given lesion under the skin and help neurosurgeons to plan their surgical approaches. Using spatial fixed points traced on the radiological scans and transposing them to the skin scalp allows the lesion to be projected or drawn on the calvaria.PMID:
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External link. Please review our .Large chondroma of the dural convexity in a patient with Noonan's s...
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):241-6.Large chondroma of the dural convexity in a patient with Noonan's syndrome. Case report and review of the literature.1, , , , , .1Servicios de Neurocirugía, Hospital General Yagüe, Burgos.AbstractINTRODUCTION: Intracranial chondromas are extremely rare intracranial tumours that usually arise from the skull base synchondrosis. Exceptionally, they may grow from cartilage rests within the dura mater of the convexity or the falx. They may be part of Ollier's multiple enchondromatosis or Maffuci's syndrome. We describe the case of a young male diagnosed of Noonan's syndrome that underwent resection of a large intracranial chondroma arising from the dural convexity. To our best knowledge this is the first report of such association.CASE REPORT: An 18-year-old male presented with a single generalized seizure. The patient was previously diagnosed of Noonan's syndrome on the basis of his special phenotype (Turner-like), low stature, cardiac malformation, retarded sexual and bone development and normal karyotype. He harboured mild psychomotor retardation. Physical and neurological examinations were unremarkable. Brain Magnetic Resonance image showed a large well-circumscribed intracranial mass in the dural convexity of the left frontal-parietal lobes, with heterogeneous contrast enhancement and no peritumoural oedema. The patient was initiated on valproic acid and underwent craniotomy and complete excision of the tumour. The tumour was firm, white-greyish, avascular and could be finely dissected away from the cortex. Postoperative seizures required additional anticonvulsant therapy. He was discharged uneventfully. The pathological study revealed a mature chondroma. Subsequent brain MRI studies have shown no evidence of recurrence after 33 months of follow up.DISCUSSION: Chondromas comprise less than 0.3% of intracranial tumours. Only twenty-five cases of intracranial dural convexity chondromas are reported in the literature. Several hystopathogenetic theories have been proposed: metaplasia of meningeal fibroblasts and perivascular meningeal tissue, traumatic or inflammatory cartilaginous activation of fibroblasts and growth of aberrant embryonal cartilaginous rests in the dura mater. Chondromas present clinical features similar to meningiomas. CT scan imaging shows a mass of variable density due to different degrees of calcification with minimum to moderate contrast enhancement. MRI studies show a well-circumscribed lesion without surrounding tissue oedema, that exhibit heterogeneous signal with intermediate to low intensity on T1-weighted images and mixed intensity on T2-weighted images with minimum enhancement. Angiogram is clue to differentiate from meningiomas since chondromas are completely avascular. Complete tumour resection including its dural attachment is the treatment of choice. Long-term prognosis is favourable. Radiation therapy is currently not recommended for residual tumours or inoperable patients due to risk of malignization. Noonan's syndrome (also known as pseudo-Turner syndrome) is a complex familial genetic disorder with a phenotype that resembles that of Turner's syndrome but exhibits no chromosomal defect. No predisposition of Noonan's syndrome for tumoural development is reported in the literature. Association of a dural convexity chondroma with Noonan's syndrome is unique as far as the literature is concerned.PMID:
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External link. Please review our .cerebral contusion
cerebral contusion的用法和样例：
Cerebral in tracellular free calcium significantly increased after cerebral contusion.
脑挫伤后脑细胞内游离钙明显增加。
Objective To explore the operative treatment of cerebral contusion and laceration in frontallobe.
目的探讨额叶脑挫裂伤的手术治疗方法。
Conclusion: MRI can increase diagnostic sensitivity in recognizing cortical cerebral contusion and laceration, and deep cerebral contusion and laceration.
结论：MRI能明显提高脑叶挫裂伤和脑深部挫裂伤诊断敏感性，减少漏诊和误诊。
Conclusion The patients with cerebral contusion and laceration in frontal lobe is quite stable,rather localized,have not developed to brain hernia and has significant occupan...
结论对于病情比较稳定的额叶脑挫裂伤,且脑挫裂伤比较局限、占位效应明显、但尚未形成脑疝者,适宜经眉切口锁孔开颅减压术。
Results The main cause of acute encephalocele were delayed intracranial hematomas,acute diffuse brain swelling,cerebral contusion and laceration in Sylvain tissue and ischemic anoxia.
结果迟发性颅内血肿、弥漫性脑肿胀、侧裂区脑挫裂伤、脑组织缺血、缺氧等是重型颅脑损伤术中急性脑膨出的主要原因。
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